disable Horizontal Mouse Scrolling wacom pen?

When I press the wacom pen somewhere in my timeline, the timeline is scrolling. The blue indicator jumps to the left en the timeline is scrolling to the left too. Very annoying!

It also occurs when I want to use the red button to drag my soundclips vertically in my timeline. When I do that, the timeline is scrolling too because of the press of the pen. It's hard to get the clips on the right place.